The present invention relates to rotary tools and, more particularly, to rotary tool which have two operating surfaces for simultaneous processing of the workpiece.
Various rotary tools are currently in use. In certain applications it is desirable to operate on two portions of the workpiece. Thus, for example, in finishing a slab of wood which is to become a table top it may be desirable to give both the top and top of the edge of the slab a rounded appearance.
One way of accomplishing this is to first operate on the top surface and then on the bottom, or vice versa. A disadvantage of finishing the workpiece sequentially is that it is difficult to maintain a uniform spacing between the two regions being operated on so that the result may be an edge which is less than completely uniform.
To overcome this difficulty, a number of rotary tools have been developed which have two cutting tools, each properly oriented, mounted on the same rotating shaft. The two tools are mounted so that they have a fixed spacing relative to each other. Use of such a tool thus allows the user to simultaneously operate on two regions of the workpiece, leading to a much more uniform product.
A disadvantage of such two-tool rotary devices is that the spacing between the two (or more) tools is fixed so that a single tool can only be used for a given spacing. Thus, for example, a series of tools, each with a different fixed spacing between the tools, must be kept on hand in order to accommodate the variety of jobs to be encountered. Furthermore, even with a series of differently spaced devices, there often arises a need for a spacing which is intermediate between two available devices.
There is thus a widely recognized need for, and it would be highly advantageous to have, a rotary device having two or more tools for simultaneously operating on two or more regions of a workpiece, where one or more of the tools is mounted so that the spacing between adjacent tools can be varied substantially continuously.